When dust is accumulated on an image capturing module or an illumination module in a document image capturing device such as a scanner having the image capturing module, the illumination module, etc., for capturing an image of a document, vertical noise, etc., occurs in the read image, and therefore, the document image capturing device is required to have a high degree of dust proof performance. On the other hand, in the document image capturing device, not only PPC (Plain Paper Copier) paper but also thick media such as thick paper, card, etc., may be used as documents. In such a document image capturing device, the image capturing module or the illumination module is provided to be movable in accordance with the thickness of a conveyed document, so that thick media such as thick paper, a card, etc., are reliably conveyed.
In the past, in such document image capturing device, a deformable sponge member is filled between the image capturing module and the illumination module to prevent any dust from entering therein. However, when the image capturing module or the illumination module is repeatedly moved, the sponge member is deformed, and this changes the load that is generated when the image capturing module or the illumination module moves, and makes it impossible to correctly convey a document. When the sponge member is deformed to some extent, a gap is generated between the image capturing module and the illumination module, which may reduce the dust proof performance.
An image forming apparatus having an image reading module having a reading frame, a reading guide, and a seal mechanism is disclosed. The seal mechanism includes a rib vertically provided in parallel with the slide direction of the reading guide and a dust proof sheet having flexibility and arranged so that its end comes into contact with the rib, and is configured to cover the gap of the reading frame and the reading guide (see Patent Japanese Laid-open Patent Publication No. 2012-39207).
An image reading apparatus causing image reading means to read an image of a document moving in document reading glass is disclosed. In the image reading apparatus, a slider for holding the document reading glass is held to be slidable in a sub-scanning direction along a feeding direction of a document by a holding module. In addition, a shield member is attached so as to shield a space portion between the holding module and the slider at the downstream side in the movement direction of the document (see Japanese Laid-open Patent Publication No. 2007-201888).